I had a teacher who told me that he never put 20 and it was his. Even my technical drawing teacher said that. In the end, it was just a challenge and a test imposed on everyone.
I managed to get a 20 with both, it felt good, but there is nothing after that. Simple, satisfaction and that you can validate everything you set your mind to. Kids today must learn to fight and not be bowed down by tests and words from teachers.
Life is about challenging yourself.
RE: The difference a teachers approach can make - Positive vs negative